I think most folks have witnessed the human side of your question...in anecdotes of people craving something because their body needs it. Pregnant women craving things from salty potatoe chips to handfuls of dirt because they need that mineral or food for something.
When i am stuffed up and can't breath well all I want is eucalyptus since it will be the only thing i can smell at the same time and we might want a salty
chicken broth since salty is all we can taste.
as for the plant side of the question I only know anecdote......I do feel like plants have been stalking me!
I have been stressed out this last year since a surgery that I had in 2010. maybe depressed at the same time. This spring I kept walking past this giant comfrey bush and FEELING like it must be special because it looks so different than the rest of the woods on the edge of my
yard. I had to figure out what it was.
Then later I found a small cluster of cammomile growing next to my patio in the rocks. I thought "I am going to save this and transplant it to my herb garden". My Husband notices and tells me that we have a bunch in the drive way. I then realize that I have a 50 yard landing strip of solid cammomile. Our driveway had been redone and this was the first thing to grow in this year!
What would a herbalist recomend to a stressed out and sad Lady? Maybe Comfrey and cammomile tea! I honestly felt like the plants were trying to physically reach out and grab me "Hello...we are right here! you need us"
the comfrey and cammomile tea tastes so sweet to me, it totaly hits the spot! Just what I needed.
I now ask myself often. "Do I love
gardening because of all that I can grow -OR- Do these plants want to grow because they love me"? I too have a hard time getting both right and left brain wrapped around that :0)